fix(cli): point at an API key where the device flow is not served

hud/cli/login.py

@@ -69,6 +69,12 @@ def _request_device_code(client: httpx.Client, hud_console: HUDConsole) -> dict[
         hud_console.info(f"HUD_API_URL={_api_url()}")
         raise typer.Exit(1) from exc
 
+    if response.status_code == 404:
+        hud_console.error(f"No browser login at {_api_url()}{DEVICE_CODE_PATH} (404).")
+        hud_console.info("This HUD deployment does not serve the device flow.")
+        hud_console.info(f"Get your key at: {settings.hud_web_url}/settings")
+        hud_console.info("Set it via: hud set HUD_API_KEY=your-key-here")
+        raise typer.Exit(1)
     if response.status_code != 200:
         hud_console.error(f"HUD API returned {response.status_code} when starting login.")
         hud_console.info(response.text[:500])

hud/cli/tests/test_login.py

@@ -0,0 +1,69 @@
+"""CLI behavior when the platform serves no browser login.
+
+``hud login`` speaks the device flow (RFC 8628) to ``/auth/device/code``. A
+deployment that does not serve that endpoint answers 404, and the command used
+to print the status code and the body, which reads as an outage rather than as
+the one thing the user can do about it: authenticate with an API key instead.
+
+The transport is mocked rather than the module's own helpers, so the command
+runs its real request path and the assertions are on what a user sees.
+"""
+
+from __future__ import annotations
+
+from typing import TYPE_CHECKING
+
+import httpx
+from typer.testing import CliRunner
+
+from hud.cli import app
+from hud.cli import login as login_module
+
+if TYPE_CHECKING:
+    import pytest
+
+runner = CliRunner()
+
+
+# Bound before any test replaces the name, so the factory below builds a real
+# client rather than calling itself.
+_HTTPX_CLIENT = httpx.Client
+
+
+def _client_serving(response: httpx.Response):
+    """A drop-in ``httpx.Client`` whose every request gets *response*."""
+
+    def factory(*args: object, **kwargs: object) -> httpx.Client:
+        return _HTTPX_CLIENT(transport=httpx.MockTransport(lambda _request: response))
+
+    return factory
+
+
+def test_login_points_at_an_api_key_where_the_device_flow_is_not_served(
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    monkeypatch.setattr(
+        login_module.httpx,
+        "Client",
+        _client_serving(httpx.Response(404, json={"error": "not_found"})),
+    )
+
+    result = runner.invoke(app, ["login", "--quiet"])
+
+    assert result.exit_code == 1
+    assert "404" in result.output
+    assert "hud set HUD_API_KEY" in result.output
+
+
+def test_login_reports_any_other_failure_as_it_finds_it(monkeypatch: pytest.MonkeyPatch) -> None:
+    monkeypatch.setattr(
+        login_module.httpx,
+        "Client",
+        _client_serving(httpx.Response(503, text="upstream is down")),
+    )
+
+    result = runner.invoke(app, ["login", "--quiet"])
+
+    assert result.exit_code == 1
+    assert "503" in result.output
+    assert "upstream is down" in result.output